As the display technology advances, the RGB color space is commonly used in virtually every computer system as well as television, video etc. The RGB color space is easy to implement although it is non-linear with visual perception. In order to be displayed on RGB displays, images and videos coded in YUV space are converted into RGB signals (usually the 24-bit RGB true color signals).
Research has shown that the human eye is capable of distinguishing around 10 million different colors under optimal viewing conditions. The traditional true color display with 8-bit precision on each channel can display about 16.7 million colors, which is more than 10 million. However, the true color display is still not sufficient for human vision perception. This is mainly because of the non-uniformity, in the sense of human perception, of the RGB space. The non-uniformity leads to the result that in some regions of the RGB color space the different colors are perceived the same and in some other regions the colors jump by more than one JND (just noticeable difference). Therefore on the one hand, to reduce the color differences of neighboring quantization levels, higher bit-depth displays, including the higher bit processing chips and drivers, are becoming a trend in the display industry. On the other hand, with the existing color display that cannot achieve continuous perceptual colors, image processing methods are expected to produce perceptually better images.
The human visual system is much more sensitive to luminance than to chrominance. Research has shown that the human eye can distinguish roughly 463 different grayscales, which is about 9 bits, while it can only distinguish about 150 different hues and 50 different saturation levels. The traditional 24-bit true color display can display only less than 255 different shades of grayscales (considering some of them are indistinguishable), which is insufficient for human eyes. In addition, as the display is made brighter and brighter, the banding artifacts become more obvious between neighboring shades of gray scales in 24-bit displays.
In regards to converting YUV signals to RGB signals, the fact that the human vision is much more sensitive to luminance than to chrominance, makes it possible to manipulate the converted RGB color signals to preserve luminance while keeping the difference in the chrominance within a tolerable range.